Study On The Method Of Applying ERT To Measure Two-Phase Flow Parameters

Two-phase flow is the most common flow of fluid in nature, which exists in somewhere widely such as petroleum, chemistry engineering process, power, metallurgy, and so on. Because two-phase flow is changeful and complex, the real-time parameter measurement in two-phase flow is a difficult problem in the domain of international engineering and science.Among the measurement methods, by measuring the distribution of conductivity in sensing field, Electrical Resistance Tomography ( ERT ), a branch of Process Tomography ( PT ), can gain abundant information of flow condition even to get various characteristic parameters of measured objectives without interfering or even destroying the field.Based upon two-phase flow's characters and Electrical Resistance Tomography technique, the author applied ERT system to measure characteristic parameters of two-phase flow, such as flow regime and cross-correlation velocity, for the future industrial application.And the author has accomplished the tasks in the thesis as follows: 1. Grounded on basic principle of ERT and structure of ERT Data Acquirement System, the discrimination and evolution of the prototype systems in function modules have been presented. The function modules of the new ERT system based on Digital Signal Processor ( DSP ) have been achieved, including the control strategy, exciting unit, electrodes switching unit, signal processing unit and external/internal interrupt in DSP.2. Based on characters of flow regimes of gas/water two-phase flow in horizontal pipes, discrete coefficient (C.V.), extracted from data of each frame, has been put forward to reflect the distribution of the cross section as a characteristic value. By taking these characteristic values as continuous-discrete time series, the K-means method of dynamic cluster methods has been applied in the paper to divide the data of the time series into two classes without reconstructing images. The results have been judged by the subjection function and distance of two cores. Then the flow regimes can be recognized well.3.Dual-plane ERT system has been adopted to experiment on oil/gas/water three-phase flow equipment. The correlation method based upon extracted...